An American company has been brought in to have a fresh look at how the historic Forth Rail Bridge is maintained.

Pittsburgh-based coatings specialist KTA-Tator is due to produce a report by the end of next month.

Network Rail said that any savings identified by the study would be invested in the rail network.

More than £30m has been spent on the refurbishment and maintenance of the structure since 1997.

Network Rail has announced its intention to invest a further £11m on painting, repairs and other work on the Forth Bridge this year.

Scottish director Janette Anderson said the company was conscious of the high esteem in which the bridge is held.

We hope to incorporate any recommendations they make into our overall strategy for this symbol of Scottish engineering achievement

Janette AndersonNetwork Rail

"For that reason we have engaged American coatings specialist KTA to have another look at the bridge and the methods we currently use to maintain and refurbish the structure," she said.

"They will report to us by the end of May, and we hope to incorporate any recommendations they make into our overall strategy for this symbol of Scottish engineering achievement.

"We anticipate this report will build on the good work carried out over the past year, and ensure any resulting savings to the overall expenditure - which are significant for a structure of this size - can then be invested in the rail network."

The bridge, which crosses the River Forth between South Queensferry and North Queensferry, is used by 150 passenger and freight trains every day.

The 113-year-old structure is also a major tourist attraction.

There has been some criticism of the bridge's appearance recently, although its safety has not been questioned.

Sections replaced

Network Rail said more than £10m had been spent on the bridge since a new seven-year contract began last April, with an further £11m of investment planned this year.

Over the coming year, an average of 150 people will be working on the bridge at any one time.

The bridge will be closed during the summer for maintenance work which will enable sections to be replaced and areas close to the tracks can be painted.

The 1.5 mile long cantilever rail bridge will be closed on all four weekends in July.